1. Field of the Invention
The present invention relates to a technical field of an organic EL panel used for a display device such as a display monitor and a method of producing the organic EL panel.
2. Related Art
In a conventional technique, an organic electro luminescence (EL) panel is known as a panel used for a display device such as a display monitor. This organic EL panel has a transparent substrate and an organic luminescent layer, which is sandwiched between an anode and a cathode and positioned above the transparent substrate. In the organic luminescent layer, a hole injected from the anode and an electron injected from the cathode recombine to thereby excite organic molecules for emitting light. This organic luminescent layer is formed to emit light only from a light emitting portion which corresponds to a design such as a character and a graphic for displaying the design.
As a patterning method of the light emitting portion of the design, a method (a) of providing an insulating layer or a layer which extremely break a balance of injecting holes and electrons between the electrodes at positions corresponding to other than the light emitting portions is known. Further, as another method of patterning the light emitting portions, a method (b) of providing any one of an anode and the cathode, which sandwich the organic luminescent layer, only at positions corresponding to the light emitting portions is known. Further, as another patterning method of the light emitting portions, a method (c) of applying a mask, which is made of, for example, a metal plate with portions corresponding to the light emitting portions punched out and is heated to have a high temperature, to an organic EL panel having an organic luminescent layer all over an anode, to thereby degenerate an organic composition forming parts other than the light emitting portions of the organic luminescent layer is known.
However, according to the above patterning methods (a) and (b), since all layers are patterned, there is a problem that processes of applying a resist on to the layers and exposing the layers to light are necessary and therefore extensive labor is required. Further, according to the above patterning methods (a), (b) and (c), when it is required to obtain an organic EL panel having a plurality of light emitting modes, masks corresponding to each of the patterns are necessary. In order to form such a mask, there are problems that additional labor is required and a cost for producing the organic EL panel increases.